Antibody response to hepatitis B vaccine is independently associated with hepatitis B breakthrough infection among adults: Results from a three-year follow-up study in China

A Novel Insertion in the Hepatitis B Virus Surface Protein Leading to Hyperglycosylation Causes Diagnostic and Immune Escape

Chronic hepatitis B virus (HBV) infection is a global health threat. Mutations in the surface antigen of HBV (HBsAg) may alter its antigenicity, infectivity, and transmissibility. A patient positive for HBV DNA and detectable but low-level HBsAg in parallel with anti-HBs suggested the presence of immune and/or diagnostic escape variants. To support this hypothesis, serum-derived HBs gene sequences were amplified and cloned for sequencing, which revealed infection with exclusively non-wildtype HBV subgenotype (sgt) D3. Three distinct mutations in the antigenic loop of HBsAg that caused additional N-glycosylation were found in the variant sequences, including a previously undescribed six-nucleotide insertion. Cellular and secreted HBsAg was analyzed for N-glycosylation in Western blot after expression in human hepatoma cells. Secreted HBsAg was also subjected to four widely used, state-of-the-art diagnostic assays, which all failed to detect the hyperglycosylated insertion variant. Additionally, the recognition of mutant HBsAg by vaccine- and natural infection-induced anti-HBs antibodies was severely impaired. Taken together, these data suggest that the novel six-nucleotide insertion as well as two other previously described mutations causing hyperglycosylation in combination with immune escape mutations have a critical impact on in vitro diagnostics and likely increase the risk of breakthrough infection by evasion of vaccine-induced immunity.

Long-term persistence of anti-HBs after hepatitis B vaccination among isolated anti-HBc positive adults in China: 8-years results

The long-term persistence of hepatitis B surface antibody (anti-HBs) after hepatitis B vaccination among adults harboring isolated hepatitis B core antibody (anti-HBc) is not yet clarified. The present study aimed to assess the immunogenicity and persistence of antibodies in adults 8 years after vaccination. A total of 309 participants including 94 participants in the isolated anti-HBs group and 215 in the control group were recruited in this study. All subjects received three doses of hepatitis B vaccine (20 μg) at 0, 1, and 12 months, followed by testing for serological responses 1 month after the third vaccination. Subsequently, 154 participants were excluded because their anti-HBs data of 8 y after the first vaccination were missing. The prevalence of isolated anti-HBc was about 11.5%, the positive seroprotection rate was 72%, and the geometric mean titer (GMT) value of anti-HBs titer was 24.55 mIU/mL in the isolated anti-HBc group 8 y after three doses of vaccination. No significant difference was detected in the positive seroprotection rate (P = .434) and the GMT values of anti-HBs titers (P = .674) between the isolated anti-HBc and control groups after 8 y. In conclusion, isolated anti-HBc-positive subjects could achieve satisfactory long-term immune effects after hepatitis B vaccination. The GMT values of anti-HBs titers were lower than those of the control group at 1 month, but no significant difference was detected after 8 years.